Sunflower diseases control by biological fungicides

The demand for organic food has grown rapidly over the last 25 years in many countries of the world. Organic farming standards require the application of biological products of disease control. The article presents the material on studying the effectiveness of fungicides based on microbiological antagonists against sunflower diseases. We carried out the study in 2020-2021 at V.S. Pustovoit All-Russian Research Institute of Oil Crops (VNIIMK) (Krasnodar). We established that the fungicides Geostim Fit type E, WS based on microbiological antagonists did not reduce the germination of sunflower seeds and actively suppressed seed infection. Their effectiveness against Alternaria spp. reached 50-74 %, against Rhizopus spp. – 74–100 %, against bacteria – 76–80 %. Double treatment of sunflower plants with BFTIM, WS (different strains) reduced the frequency of bacterial blight to 37 %, of dry rot – to 60 %, of Alternaria blight – to 39 %, of Phoma rot – to 41 %, and of Fusarium blight – to 75 %. The application scheme of Geostim Fit E (G), WS; BFTIM (E), WS; BFTIM (Zh), WS showed the best economic effectiveness with a seed yield of 3.56 t/ha, net income of 122 910 rubles, and profitability of 311 %.

Influence of ultraviolet irradiation of perennial grasses seeds on their sowing quality

A new direction in pre-sowing seed preparation is environmentally friendly and energyefficient ultraviolet irradiation, which increases germination, reduces seed infection, and improves growth force. In this regard, the experiment of studying the effect of UV irradiation on the sowing qualities and morphophysiological parameters of the seeds of the birds-foot trefoil and awnless brome was laid at the UdmFRC UB RAS in 2019. Use of UV rays of range A with a wavelength of 315–400 nm for 5 min reduced the infection of the birds-foot trefoil seeds by 3.2%, increased the length of the sprout by 0.81 cm and the strength of growth — by 5.4% in comparison with untreated seeds. There was also a tendency for a decrease in seed hardness by 2.5%, an increase in root length by 0.41 cm, and the degree of seedling development by 0.12 points. The most effective for awnless brome seeds was UV treatment for 35 minutes, which led to an increase in germination by 14.5%, a decrease in seed infection by 5.8%. There was also a tendency to improve the morphological parameters of seedlings: the length of the sprout increased by 0.9 cm, the length of the root — by 0.88 cm, the length of the coleoptile — by 0.30 cm. The strength of growth in this variant was 9.3% higher than in the control without treatment. In general, the treatment of perennial grasses seeds with ultraviolet light reduced infection, increased laboratory germination and strength of growth, and reduced seed hardness.

Longevity of Plant Pathogens in Dry Agricultural Seeds During 30 Years of Storage

Plant diseases may survive and be spread by infected seeds. In this study we monitored the longevity of 14 seed-borne pathogens in 9 crop species commonly grown in the Nordic countries, in addition to a sample of sclerotia of Sclerotinia sclerotiorum. The data from the first 30 years of a 100-year seed storage experiment located in a natural −3.5 °C environment (permafrost) in Svalbard, Norway, are presented. To date, the pathogens, tested by traditional seed health testing methods (freezing blotter, agar plates, growing on tests), have survived. Linear regression analyses showed that the seed infection percentages of Drechslera dictyoides in meadow fescue, Drechslera phlei in timothy, and Septoria nodorum in wheat were significantly reduced compared to the percentages at the start of the experiment (from 63% to 34%, from 70% to 65%, and from 15% to 1%, respectively), and that Phoma betae in beet had increased significantly (from 43% to 56%). No trends in the infection percentage were observed over the years in Drechslera spp. in barley (fluctuating between 30% and 64%) or in Alternaria brassicicola in cabbage (fluctuating between 82% and 99%), nor in pathogens with low seed infection percentages at the start of the experiment. A major part of the stored sclerotia was viable after 30 years. To avoid the spread of seed-borne diseases, it is recommended that gene banks implement routines that avoid the use of infected seeds.

Black point of winter wheat seeds

Goal. To study infection of seeds of winter wheat varieties by «black point» and to establish the phytopathogenic composition of pathogens in the Right Bank Forest-Steppe of Ukraine. Methods. Laboratory — macroscopic analysis was performed according to DSTU 4138-2002, phytopathogenic composition was identified using nutrient medium, statistical analysis of the obtained data — calculation of the degree of pathogen severity, LSD. Results. A collection of 27 varieties of soft winter wheat was studied to determine the degree of seed infection. The highest percentage of infection was found in varieties Vodogray Bilotserkivsky (Ukraine), Adele (Russia), Balitus (Austria), Viglanka (Slovakia), Sefeg-2 (Azerbaijan). The least susceptible to the disease are varieties Daria (Croatia), Bodycek (France), Gratsia Bilotserkivska (Ukraine, Bila Tserkva DSS), Azano (Sweden), Gospodarka (Ukraine), Kozyr (Ukraine), Morozko (Russia), the number of grains with signs of darkening in the embryonic zone for these varieties did not exceed 1%. The sowing qualities of the diseased seeds were determined. The species composition of phytopathogens that cause the disease has been established. The phytopathogenic complex of seeds with the «black point» included fungi of the genera Alternaria, Fusarium, Curvularia, Bipolaris, Aspergillus, Acremoniella, Stemphillium, Sordaria and Epicoccum. Most often, the seeds were colonized by fungi of the genus Alternaria Nees. Their share in the years of research was 76.6—83.1%. Conclusions. The infection of seeds of winter wheat varieties by black point under conditions of the Right-Bank Forest-Steppe of Ukraine in 2018—2019 ranged from 0 to 19.8% depending on the variety and year of research. The phytopathogenic complex included 13 species of fungi from 9 genera: Alternaria, Fusarium, Curvularia, Bipolaris, Aspergillus, Acremoniella, Stemphillium, Sordaria, Epicoccum. The part of Alternaria spp. in the years of research was over 75%, the most common species were A. tenuissima and A. infectoria. The percentage of species from other genera was insignificant and did not exceed 4.6%.

Fungal microbiota in seeds, seedlings and mature plants of raspberry (Rubus ideaus L.)

Presently, there is an intensive search for fungal endophytes to be used in agriculture for the protection and condition improvement of plants and in medicine. We screened for the presence of endophytes in raspberry, which occurs naturally in the Białowieża Forest. The fungal isolates representative of each morphotype were analysed using the molecular markers ITS1 and ITS2. In total, we found 34 taxa of endophytic fungi. The majority were potential pathogens. As many as 27 taxa were found in the leaves of mature plants. No fungi could be isolated from the surface sterilized seeds obtained from these plants. Seedlings were grown from the seeds deposited in the soil seed bank in the Białowieża Geobotanical Station of the University of Warsaw in Białowieża. 8 taxa of endophytic fungi were found in seedlings. It could be due to a possibility of seed infection with these endophytes in soil conditions.

Laboratory assessment of fungicide efficiency against seed infection of soybean

The research was conducted in the laboratory of plant protection of the agrotechnological department of the V.S. Pustovoit All-Russian Research Institute of Oil Crops in 2019. The purpose of the research was search of the effective preparations with fungicide and bacterial actions for soybean seed protection against seed infection in the lab conditions. We tested 17 fungicides of the different penetration methods and actions permitted for application in the Russian Federation, nine of which are register on soybean and nine ones have a potential effect for studying crop. Seed for lab germination were rolled in filter paper in the moister chamber due to the State Standards 12038-84 and 12044–93. Laboratory germination of soybean seed in control without treatment was equal to 61.5%, whereas in variants with protectant application – by 4.0–28.0% higher as seed infection was lowered. High biological efficiency against bacterial diseases was noted for registered on soybean fungicides Vitalon, CS (56.9%), ТМТD, WDG (51.1%), Delit Pro, CS (51.1%), and for nonregistered preparations – Prozaro, EC (53.2%), Tebu 60, OE (43.6%) and Prozaro Quantum, EC (40.4%) as infection in control was equal to 46.0%. Fusariose infection of soybean seeds and seedlings was lower than with bacterial disease and equal to 17.0% in control. Among registered on soybean preparations Spirit, SC (93.9%), Acanto Plus, CS (88.3%), Maxim Gold, CS, Vitalon, CS (82.2%), Delit Pro, КС (72.0%) demonstrated effectiveness against fusariose at efficiency of etalon ТМТD, WSC of 32.0%. Among non-registered preparation effective were Lamador, CS and Zato, WDG (100%), Oplot Trio, WSC (82.2 %), Redigo Pro, CS (73.7%) and Raxil Ultra, CS (68.0%). Due to results of laboratory testing, Vitalon, CS; Prozaro, CE; Prozaro Quantum, CE; ТМТD, WSC; Tebu 60, OE and Delit Pro, CS are the best fungicides with bacterial effect.

Prevalence and Transmission of Fusarium moniliforme: A Seed Borne Pathogen of Rice

Fusarium moniliforme is one of the major seed borne pathogen of rice in Bangladesh that causes significant yield loss. To observe the incidence and transmission of this pathogen, farmers saved seeds and seeds from BADC were collected and the pathogens were detected by blotter method. The prevalence of the F. moniliforme varied according to locations and seasons. The highest 18% of seed infection was recorded in Boro seeds of Netrakona district and the lowest 2% was in Gazipur district. The Embryonal end of the seed is the most preferable site of the infection. F. moniliofrme successfully transmitted from seed to seedling and the transmission is high when pre- sprouted seed sown on the puddled seed bed. The study recommended that before planting season, seeds should be tested and treated when necessary to minimize spread of the pathogen. Bangladesh Rice J. 24 (1): 11-19, 2020

The impact of temperature patterns during storage of Scots pine and Norway spruce seeds on their germination and fungal infection rates

Relevance of the study. One of the ways to maintain the genetic diversity of forest-forming species is to preserve highquality seed material ex situ. However, the relationship between the diversity of pathogenic mycobiota and the duration and methods of forest tree seed storage remains underexplored. The results of research into this problem can be used in forest seed production and forest phytopathology.Materials and methods. For our study we used seeds ofРinus sylvestris L. and Picea abies (L.) Karst. of the orthodox type, harvested in the period of 1996–2011 and stored under different temperatures: +20°С, +4°С, –18°С, and in liquid nitrogen vapor (–182°С) since 2011. Prior to their storage, seed samples were dried to a moisture content of 4.2–4.4% and hermetically packed. Seed germination was tested before and after three, five and eight years of storage, following GOST 13056.6-97 standards. The level of seed infection and the composition of pathogenic fungi were assessed.Results. After eight years of storage at +20°С, pine and spruce seed germination capacity decreased by 13–60%, depending on the year of harvesting. Seed storage at –18°С and –182°С allowed us to prevent seed infection and preserve seed viability. In most cases, the germination energy and germination capacity were negatively correlated with the level of seed infection. The diversity of pathogenic (mold) fungi on the surface of seeds was represented by ten genera; the most common were saprotrophs: Aspergillus P. Micheli, Penicillium Link, Rhizopus Ehrenb., Scopulariopsis Bainier.Conclusion. At the present stage of research, the success of seed storage at low and ultralow temperatures was demonstrated. We recommend cryopreservation for the long-term storage of improved and valuable seeds.

Fermentation: an Unreliable Seed Treatment for Bacterial Fruit Blotch of Watermelon

Acidovorax citrulli is a seed-borne pathogen that causes bacterial fruit blotch (BFB), a global threat to watermelon production. Treating watermelon seeds to eliminate A. citrulli is a critical component of BFB management and several strategies have been evaluated to mitigate the impact of the disease. In China, watermelon seed producers routinely incubate seeds in watermelon juice (fermentation) to reduce the risk of seed infection by A. citrulli and seedling transmission of BFB. However, there has been limited effort to evaluate the efficacy of fermentation in mitigating A. citrulli seed infection. The current study first showed that fermented watermelon fruit juice could inhibit A. citrulli population growth, and further demonstrated that the low pH conditions, not the dynamic of temperature, generated during the fermentation process might play a major role in inhibition of growth of A. citrulli and could induce the viable but non-culturable (VBNC) state in A. citrulli. We developed an effective method that was based on PMA-PCR to detect viable A. citrulli cells under low pH conditions or in fermented watermelon fruit juice. We also provided evidence that VBNC A. citrulli cells induced by fermented watermelon fruit juice could not be resuscitated and did not retain their virulence on watermelon seedlings. However, VBNC A. citrulli cells could be resuscitated in LB medium. Based on these observations, we conclude that fermentation in watermelon fruit juice may not be an effective seed treatment for BFB as it may increase the seed infection by A. citrulli.